NS Engineers Electrical Maintenance Supervisor Interview Questions and Answers

The question covers power factor of transformer, types of DC machine, working principle of AC alternator, and DC motors.

• Power factor of a transformer is the ratio of real power to apparent power.

• Types of DC machines include DC motors and DC generators.

• AC alternators work on the principle of electromagnetic induction to convert mechanical energy into electrical energy.

• DC motors convert electrical energy into mechanical ...read more

The weight of 1m 16 mm steel depends on the density of steel.

• The weight of steel can be calculated using the formula: weight = volume x density

• The density of steel is approximately 7.85 grams per cubic centimeter

• To calculate the weight of 1m 16 mm steel, we need to calculate its volume first

• The volume of a cylinder (steel rod) can be calculated using the formula: volume = π x radius^2 x height

• In this case, the radius w...read more

Gears are mechanical components that transmit power and motion between rotating shafts. There are various types of gears.

• Spur gears are the most common type and have straight teeth.

• Helical gears have angled teeth and provide smoother operation.

• Bevel gears transmit power between shafts that are not parallel.

• Worm gears have a screw-like thread and are used for high reduction ratios.

• Planetary gears have a central gear tha...read more

Stress is the force applied per unit area, while strain is the deformation caused by stress.

• Stress is measured in units of force per unit area, such as pounds per square inch (psi) or newtons per square meter (N/m²).

• Strain is the ratio of the change in length or shape of an object to its original length or shape.

• Stress and strain are related by the material's modulus of elasticity, which is a measure of how much the ma...read more

A centrifugal pump is a mechanical device that uses centrifugal force to transport fluids. There are two types: radial and axial.

• Centrifugal pumps are commonly used in industrial and domestic applications.

• Radial pumps have a volute casing and are used for low flow and high head applications.

• Axial pumps have a propeller and are used for high flow and low head applications.

• Centrifugal pumps are easy to install and mainta...read more

SI and CI engines are types of internal combustion engines used in vehicles and machinery.

• SI engine stands for Spark Ignition engine, also known as gasoline engine.

• CI engine stands for Compression Ignition engine, also known as diesel engine.

• SI engines use a spark plug to ignite the fuel-air mixture, while CI engines use compression to ignite the fuel.

• SI engines are commonly used in cars, motorcycles, and small machine...read more

Knocking is a phenomenon where the air-fuel mixture in the engine cylinder ignites spontaneously before the spark plug fires.

• Knocking is also known as detonation or pinging.

• It can cause engine damage if not addressed.

• It occurs when the air-fuel mixture in the cylinder ignites prematurely due to high pressure and temperature.

• It can be caused by low-quality fuel, incorrect ignition timing, or engine overheating.

• To preven...read more